Effect of moisture on leaf litter decomposition and its contribution to soil respiration in a temperate forest

Cisneros Dozal, L.M. , Trumbore, S. and Hanson, P.J. (2007) Effect of moisture on leaf litter decomposition and its contribution to soil respiration in a temperate forest. Journal of Geophysical Research, 112, G01013. (doi: 10.1029/2006JG000197)

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The degree to which increased soil respiration rates following wetting is caused by plant (autotrophic) versus microbial (heterotrophic) processes, is still largely uninvestigated. Incubation studies suggest microbial processes play a role but it remains unclear whether there is a stimulation of the microbial population as a whole or an increase in the importance of specific substrates that become available with wetting of the soil. We took advantage of an ongoing manipulation of leaf litter <sup>14</sup>C contents at the Oak Ridge Reservation, Oak Ridge, Tennessee, to (1) determine the degree to which an increase in soil respiration rates that accompanied wetting of litter and soil, following a short period of drought, could be explained by heterotrophic contributions; and (2) investigate the potential causes of increased heterotrophic respiration in incubated litter and 0–5 cm mineral soil. The contribution of leaf litter decomposition increased from 6 ± 3 mg C m<sup>−2</sup> hr<sup>−1</sup> during a transient drought, to 63 ± 18 mg C m<sup>−2</sup> hr<sup>−1</sup> immediately after water addition, corresponding to an increase in the contribution to soil respiration from 5 ± 2% to 37 ± 8%. The increased relative contribution was sufficient to explain all of the observed increase in soil respiration for this one wetting event in the late growing season. Temperature (13°C versus 25°C) and moisture (dry versus field capacity) conditions did not change the relative contributions of different decomposition substrates in incubations, suggesting that more slowly cycling C has at least the same sensitivity to decomposition as faster cycling organic C at the temperature and moisture conditions studied.

Item Type:Articles
Keywords:leaf litter, radiocarbon, soil respiration, litter moisture
Glasgow Author(s) Enlighten ID:Cisneros, Dr Malu
Authors: Cisneros Dozal, L.M., Trumbore, S., and Hanson, P.J.
Subjects:Q Science > Q Science (General)
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Journal of Geophysical Research
Journal Abbr.:J. Geophys. Res.
Publisher:American Geophysical Union (AGU)
Copyright Holders:Copyright © 2007 AGU
First Published:First published inJournal of Geophysical Research 2007 112:G01013
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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